The designation "dwarf"
conifer means that it is a cultivar (cultivated variety) that is slower
growing and will have a smaller mature size than the naturally
occurring species. For example, if the species can attain 60 feet
mature size in its natural range, a cultivar that matures at 50 feet is
still considered a dwarf form! The American Conifer Society has
designated 4 distinct categories of dwarf conifers based on mature size and
growth rate. A more appropriate term for the homeowner might be
"garden conifer".

Keep in mind, the
following factors will affect differences in annual growth rate, as is true
with any plant.

Regional variations

Climate

Precipitation and
atmospheric moisture

Soil fertility, pH,
composition, etc.

Stress

Your own yard's
microclimates

What makes a conifer dwarf?

Seed provides genetic variation and mutations. Mutations of the species (wild type)
parent plant are identified, selected, and propagated.

Variations in top growth (scion) due
to which rootstock it is grafted on

Clonal (vegetative propagation) –
most mutations and brooms are grafted onto rootstock to produce a cultivar.
Many genera do not propagate easily from cuttings. Exceptions are yew,
arborvitae, and some falsecypress.

Large dwarf conifers are
more appropriate for larger sites and may not be as useful for the homeowner
with a smaller lot. Intermediate and dwarf categories work well for
the average to small yard. Miniatures need space around them and don't
compete with other landscape plants. They are more desired for rock
gardens, containers, garden railways, and small water features.